Microstructure, Mechanical Properties and Oxidation Resistance of Nb-22Ti-14Si-2Hf-2Al-xCr Alloys

详细信息	查看全文 | 推荐本文 |

• 作者：Ligang WANG ^{buaawlg@163.com}  ; [Author Vitae] ; Lina JIA ; Renjie CUI ; Lijing ZHENG ; Hu ZHANG ; ^{zhanghu@buaa.edu.cn}  ; [Author Vitae]
• 关键词：arc-melted alloys ; Nb-Si alloys ; microstructure ; mechanical properties ; oxidation resistance
• 刊名：Chinese Journal of Aeronautics
• 出版年：2012
• 期刊代码：3_10009361
• 类别：et
• 出版时间：April, 2012
• 卷：25
• 期：2
• 页码：292-296
• 文件大小：1082 K

摘要

Nb-22Ti-14Si-2Hf-2Al-xCr (x=2, 6, 10, 14, 17 at%) alloys are prepared by arc-melting under argon atmosphere. Microstructural characteristics, mechanical properties and oxidation resistance of the arc-melted alloys are investigated. At 2 at%Cr content, the microstructure is composed of Nbss, Nb₃Si and a small quantity of Nb₅Si₃, when the Cr contents increase, Nb₃Si disappears. For the high Cr content (x 鈮?10 at%alloys, besides the Nbss and Nb₅Si₃, Cr₂Nb is also detected. With the increase of Cr content, the volume fractions of Cr₂Nb and Nb₅Si₃ increase, while that of Nbss increases firstly and then begins to degrade when the Cr content is higher than 6 at%. For the alloy with 2 at%Cr, the room temperature fracture toughness is about 14.5 MPa路m^1/2, but badly decreases to about 8.5 MPa路m^1/2, when the Cr contents increase. Vickers hardness of Nbss tends to increase linearly from about 400 to 500, while that of silicides is not sensitive to Cr contents, about 950. The appearance of Cr₂Nb phase significantly improves the high temperature oxidation resistance of the alloys with high Cr contents. The isothermal oxidation tests show that the oxidation kinetics of the alloys with various Cr contents follows parabolic oxidation kinetics.